OpenBSD Errata: November 29th, 2018 (qcow2)

Errata patches for vmd have been released for OpenBSD 6.4.
Writing more than 4GB to a qcow2 volume corrupts the virtual disk.
Binary updates for the amd64 and i386 platforms are available via the
syspatch utility. Source code patches can be found on the errata page:
https://www.openbsd.org/errata64.html
After patching, restart the vmd service.